Typical lithium-ion batteries utilize carbon anodes and lithiated transition metal oxide cathodes separated by an ion-permeable separator material. Higher charge density can be attained by utilizing porous silicon anode in place of carbon. These types of batteries currently dominate the battery market in the area of cellular phones, cameras, computers, and other electronic equipment. Problematic areas for these batteries, particularly in rugged applications, include safety, life span, and cost.
One source of failure in lithium-ion batteries involves the formation of dendrites within the battery. Dendrites are elongated, microscopic metal deposits that can form within the cell. Known causes of dendrite formation include manufacturing defects, over charging, and rapid charge at cold temperatures. Dendrite formation generally begins in the anode and creates an internal short once dendrites extend through the separator material to the cathode. Overcharging and overly rapid charging are believed to build up excessive concentrations of lithium ions in the electrolyte near the electrodes before the lithium ions can be conveyed to the opposite electrode, thereby forming a dendrite upon exceeding the solubility limit. Shorts caused by dendrites can lead to a catastrophic battery failure. Although the cause of recent Boeing 787 fires has not yet been determined, there has been some speculation that they resulted from dendrites. There is currently no method to reliably detect the presence of dendrites within a battery.
In view of the foregoing, batteries incorporating dendrite detection technology and methods for detecting dendrites would represent a substantial advance in the art. The present disclosure satisfies these needs and provides related advantages as well.